In general, robots used as industrial robots and so forth are configured as multi-axis robots, each of which is provided with a plurality of motors that drive moving members necessary for operating the robot. When operating such a robot, the plurality of motors are operated at the same time to control the robot, and the robot is configured such that a safety circuit operates at the time of an emergency stop (see Patent Literature 1, for example).
In the conventional robots, the power of the motors is completely shut off by the safety circuit. In order to ensure that the motors will become unable to operate, such a conventional robot adopts, for example, a system that mechanically shuts off, by a magnet contactor, the power supply line of a three-phase AC power supply that operates the motors.